1. Thermo-mechanical Analysis
Solid Breeder TBM Analysis
Thermo-mechanical Analysis
Zhiyong(John) An
Mechanical & Aerospace Engineering Department
University of California Los Angeles
March 3rd, 2005

2. Effective mechanical properties
The effective properties for the pebble bed are different from that of the bulk material. They show a nonlinear behavior. Commonly the mechanical properties of a packed pebble bed is function of stress, temperature and material properties.
Nonlinear elastic modulus
Thermal creep modulus
where
where
: Young’s modulus [MPa]
: creep strain
: Initial Young’s modulus [MPa]
: Von Mises Stress [MPa]
: Von Mises Stress [MPa]
: Temperature [℃]
: Temperature [℃]
: Time [s]
: Coefficients
: Coefficients

3. Blanket Evaluation (submodule)
The unit cell of ITER TBM

4. Blanket Evaluation (Submodule 2-D result)
Layer breeding design
The characteristic stress and deformation magnitudes of Layer breeding Unit
(a) The results at the mid-layer
Distance from side wall [mm]
(b) The results of the maximal stress point
The time dependent behaviors of Layer breeding Unit

5. Blanket Evaluation (Submodule 2-D result)
Edge-on breeding design
(a) Prototype model
(b) ITER scale model
The time dependent behaviors of Edge-on breeding Unit

6. Blanket Evaluation (New version)
The unit cell of ITER TBM
The box cell

7. Coolant Panel / Breeder Bed
Structures in FEM Modeling

8. 3-D T & Stresses distribution
δmax= mm
at z ~ 22.1cm
from inner wall
σmax = 6.1 MPa
at z ~ 36.1cm x z
Temperature
Von Mises Stresses

9. Coolant Panel / Breeder / Be

10. Conclusions and future works
Effective Mechanical properties of pebble beds are necessary for the blanket evaluation.
Different structure configurations will have impact on the stress distribution. 2-D results show edge-on breeding design has a better feature.
Thermal creep effects will enhance the stress relaxation in the breeder pebble beds, whether it is an important factor under pulsed operations is yet to be studied.
Another issue to be considered is the cyclic effects under ITER pulsed operations.